The so-called Islamic State’s casual embrace of mass murder, barbaric executions, ethno-religious cleansing and systematic degradation of women has understandably drawn attention from the other cruel tentacles of its hydra-like malice.

One of the most chilling and consequential of these is IS’s calculated war on history — and make no mistake, these fanatics are every bit as much at war with the realities of our common past as they are with governments of Syria and Iraq. As the New York Times reported this week, IS is engaged in the wholesale destruction of mosques, shrines, statues, tombs, churches and monasteries across the broad swath of history-rich territory it now controls.

“This region has been the center of the world for every great empire recorded in human history,” said Candida Ross, professor of New Testament and early Christianity at Notre Dame. “We are talking about successive generations of history all in one place, all being destroyed at once.” Many other archeologists and scholars of ancient, Islamic and early Christian architecture and art are equally appalled, but reluctant to speak out for fear of drawing the media-savvy jihadis’ attention to targets they’ve so far overlooked. Before our eyes, our common patrimony — the physical artifacts critical to the study of early and medieval Christianity and Islam are being literally erased from the earth, their particular windows on history now closed to us forever.

In the immediate sense, this wholesale vandalism is a consequence of the salafist puritanism particular to IS’s brand of Sunni Islam, which regards any physical relic, representational art or venerated sacred site as a form of idolatry that must be eradicated. They hold this in common with the Wahhabi sect that holds power in Saudi Arabia and, perhaps, have been emboldened by the world’s indifferent silence over the Sauds’ decades-long campaign to erase every physical vestige of historic Islam’s origins and evolution through the ages. Since they took control in the early 1930s, the Sauds and their enablers in the Wahhabi clerical cast have destroyed the graveyards and shrines of Muhammad’s family and earliest followers, along with the mosques associated with early Islam and even the house where the prophet grew up. Historic Mecca and Medina simply are gone, their secrets foreclosed to future generations of scholars.

Imagine the howls of international outrage if the Vatican were to level old Rome to make way for a parking lot or the Israelis demolished the Temple Mount and replaced it with a shopping center. That is precisely what the Saudis have done while all the rest of the world — including its Muslims — stood by in silence. As a result, we may never be able to subject the question of Islamic origins to the same sort of searching scholarship to which the world’s other great religions have been subjected.

It’s an indifference that gives breathtaking new meaning to the “bigotry of low expectations,” but one that perfectly serves the purposes of the sort of rigid orthodoxy to which the salafists of all stripes adhere. The consciousness of history as an unfolding that occurred before we drew breath and which will continue after we breathe our last is the implacable enemy of orthodoxies of every kind, whether political or religious. Orthodoxy is a fixed set of beliefs that its adherents must believe stands at the end point of history — true always and everywhere and at every moment. “Orthodoxy means not thinking — not needing to think,” wrote George Orwell. “Orthodoxy is unconsciousness.”

It’s an unconsciousness that requires that believers live in the moment, as if there were no past, because the school of history’s unvarying curriculum is change, and the true believer holds to the notion that they are in possession of unchangeable truth, one without beginning or end. (Witness our own fundamentalists’ long rear-guard action against the biological fact of evolution.)

Political fundamentalism — mainly Communist Marxism and the authoritarian nationalist reactions to it, like fascism — were the great killing scourges of the century just past. New forms of authoritarianism have arisen unseen in this new era, strangely modernist adaptations of medieval obscurantism, like political Islam, and they have become the engines of atrocity in our own time. What these wicked creeds hold in common is the murderous totalitarian impulse.

Twenty years ago, the then-85-year-old Isaiah Berlin — wisest and most humane of 20th century political philosophers and the totalitarian impulses’ greatest interpreter — wrote of the toll single-minded political orthodoxies with their utopian illusions had inflicted during his long life. “If you are truly convinced that there is some solution to all human problems, that one can conceive of an ideal society which men can reach if only they do what is necessary to attain it, then you and your followers must believe that no price can be too high to pay in order to open the gates of such a paradise. Only the stupid and malevolent will resist once certain simply truths are put to them. Those who resist must be persuaded; if they cannot be persuaded, laws must be passed to restrain them; if that does not work, then coercion, if need be violence, will inevitably have to be used — if necessary, terror, slaughter ….

“The search for a single, overarching ideal because it is the one and only true one for humanity, invariably leads to coercion. And then to destruction, blood — eggs are broken, but the omelet is not in sight, there is only an infinite number of eggs, human lives, ready for the breaking. And in the end the passionate idealists forget the omelet, and just go on breaking eggs.” (The entirety of Berlin’s 1994 essay, written in acknowledgement of an honorary degree from the University of Toronto, can be found in the New York Review of Books’ current issue.)

At the end of his long life, Berlin took great comfort from the spread of liberal democracy that seemed to be occurring a decade ago. That tide now seems to be ebbing and new sorts of darkness are growing — in the Middle East, in Central Asia and across the “blood lands” on Europe’s eastern frontier. History and the critical thinking it engenders in its students are among the principle lights holding back the darkness old and new, which is why we must take their part whenever and wherever we can.

Tim Rutten is a columnist for the Los Angeles News Group. ruttencolumn@gmail.com.